The grid frequency is critical for maintaining stable power system operations. As grid load capacities expand, primary frequency modulation (PFM) by power stations becomes increasingly vital. Currently, most large-scale pool-type sodium-cooled fast reactors (SFRs) operate at base load, leaving the feasibility of their participation in PFM through the “reactor-follow-turbine” mode largely unexplored. This study employs an independently developed transient analysis tool to assess the viability of PFM for large SFRs. By adjusting turbine power settings and modulating primary/secondary/tertiary coolant flows, critical node parameters are stabilized. Results demonstrate that these reactors can maintain sodium temperature fluctuations at the evaporator outlet within ± 10 °C during PFM responses, under the premise of ensuring feedwater and main steam pressures remain stable throughout transient processes. This finding provides robust support for integrating large SFRs into grid PFM operations and expanding their installed capacity.